Conventionally, a liquid crystal display device has been widely used for the screen of a word processor and computer. In recent years, the liquid crystal display device has spread rapidly as a television screen. Many of these liquid crystal display devices adopt TN (Twisted Nematic) mode. However, the TN mode liquid crystal display device has the problems of tendencies to degrade a contrast and to reverse a gradation property when viewed from an oblique direction.
For this reason, in recent years, in light of the improvement in viewing angle property, a VA (Vertical Alignment) mode liquid crystal display device has been attracting attention. A liquid crystal cell of the VA mode liquid crystal display device is arranged in combination of a nematic liquid crystal having a negative dielectric ansiotropy with a vertical alignment film.
Further, for example, Japanese Patent No. 2947350 (granted on Jul. 2, 1999), as shown in FIG. 13, discloses a liquid crystal display device 101 in which a positive uniaxial film 114 and a negative uniaxial film 115 are provided between a liquid crystal cell 111 and a polarizing plate 112 and between the liquid crystal cell 111 and a polarizing plate 113, respectively, in order to compensate the optical anisotropy of the liquid crystal cell 111 when black image is displayed.
With the above arrangement, even though the liquid crystal cell 111 brings a phase difference depending on a polar angle to transmitting light when the liquid crystal cell 111 in which liquid crystal molecules are oriented vertically is viewed from an oblique direction, properly setting the respective retardations of the films 114 and 115 can compensate the phase difference. Therefore, black displaying can be performed substantially as in the case when the liquid crystal cell 111 is viewed from a front direction, that is, as in the case where the liquid crystal molecules maintain the polarizing state of the transmitting light. As a result of this, it is possible to prevent light leakage, thus enhancing the contrast and suppressing the occurrence of coloring and tone degradation when viewed from an oblique direction.
However, under the situation where a liquid crystal display device with a wider viewing angle and higher display quality is expected, there is a demand for the improvement in coloring and tone degradation caused when viewed from the oblique direction nowadays. The liquid crystal display device using the films 114 and 115 with the retardation described in Japanese Patent No. 2947350, however, is not always satisfactory and still leaves room for improvement.